All permalink structures except default return 404 for event details

When attempting to view event details from either agenda view (http://oaklandtech.com/staff/), or calendar view (http://oaklandtech.com/staff/calendar/), I get a 404 Page Not Found error.

Based on other similar forum threads with this plugin and permalink/404 problems, I have changed permalink structures, saved permalinks multiple times, cleared the ai1ec cache, disabled other plugins, changed themes…and none of these have solved the problem.

Only the default permalink structure (http://oaklandtech.com/staff/?p=123) displays event details/page properly. All other permalink structures return the 404.

https://ww.wp.xz.cn/plugins/all-in-one-event-calendar/

Can someone please provide other suggestions for this problem?